Automated turret lathe

ABSTRACT

Automatic turret lathe with a synchronous spindle in the tool turret which is drivable in synchronism with the main spindle and comprises a workpiece chuck means. To enable workpieces to also be worked on the rear side, i.e., on the side on which they were severed from a stock rod, while the next workpiece held in the main spindle is already being machined with the aid of a further tool carrier, a third tool carrier is arranged on the side of the tool turret mounted on a compound slide system facing away from the main spindle.

The invention relates to an automatic turret lathe with a main spindlecomprising a first workpiece chuck means, a tool turret displaceableparallel to the main spindle axis, and a further tool carrierdisplaceable vertically to the main spindle axis, wherein at least onestation of the tool turret has a second workpiece chuck means mounted atthe tool turret for rotation about an axis (synchronous spindle axis)and drivable in synchronism with the main spindle, and is sopositionable by adjustment of the tool turret that the synchronousspindle axis is aligned with the main spindle axis. "Flush" both hereand hereinafter does not necessarily mean "coaxially" since parallelismmay also prevail.

Such cam controlled automatic turret lathes equipped with a so-calledsynchronous device in the turret head are already known (e.g. automaticturret lathes of the types INDEX C 19 and INDEX C 29 of the applicantcompany), for cutting-off, i.e., severing a machined workpiece smoothly,i.e., without an undesired projection, from a stock rod. To this end,the machined workpiece is gripped by the workpiece chuck means which isprovided in the tool turret and is driven in synchronism with the mainspindle via a mechanical gear. After the workpiece has been severed fromthe stock rod, the tool turret is indexed .[.on.]. .Iadd.one.Iaddend.station further about its axis of rotation. The workpieceremains in the workpiece chuck means of the tool turret until, afterseveral rotational indexing steps of the tool turret, it has beenswivelled through a total of 180°, whereupon the workpiece chuck meansis opened and the workpiece is conveyed by a resilient ejector held inthe turret into a groove via which the workpieces are transported out ofthe machining area of the automatic lathe. In these known automaticlathes, the synchronous device can, however, also be used for performingsimple machining on the cut-off side of the workpiece; to this end, theworkpiece chuck means of the tool turret is driven further after theworkpiece has been cut-off from the stock rod, and the workpiece is thenmachined by a tool which is held by a tool carrier which like the toolcarrier for the cutting-off tool is arranged beside the main spindleworkpiece chuck means. While this work is being performed, a newworkpiece cannot be machined since the stock rod is unable to be pushedforward during this time.

The known synchronous device does, however, also have a furtherdisadvantage: the workpiece is gripped in the turret workpiece chuckmeans by the tool turret being displaced parallel to the main spindleaxis and an actuating member of the chuck means which is mounted at thetool turret coming to rest against a stop member. While a workpiece onwhich the machining has actually been completed is gripped in the turretworkpiece chuck means, a relative motion therefore necessarily occursbetween the workpiece still held on the stock rod and this workpiecechuck means.

The object underlying the invention was to provide an automatic turretlathe with a so-called synchronous device, with which a workpiece can bemachined on the rear side, i.e., on the side on which it was severedfrom the stock rod, while the next workpiece held in the main spindleworkpiece chuck means is already being machined.

Departing from an automatic lathe of the kind mentioned at the outset,this object is attained by a third tool carrier being arranged on theside of the tool carrier in the form of a tool turret facing away fromthe main spindle, and by at least one of these two tool carriers beingmounted on a compound slide displaceable parallel and vertically to themain spindle axis. The solution according to the invention may beapplied with special advantage to NC automatic turret lathes as theyenable in a simple way rotation of the tool turret through severalstations at once after a workpiece has been cut-off, so that themachining of the next workpiece in the main spindle workpiece chuckmeans is not hindered so long as the workpiece previously manufacturedis being machined by one or several tools of the third rear toolcarrier. The arrangement of the tool turret or the third tool carrier ona compound slide also enables motion of the workpiece held in the turretworkpiece chuck means in any direction with respect to the rear toolcarrier, so that the most varied kinds of machining may be performed.

A preferred embodiment of an NC automatic turret lathe according to theinvention comprises two tool turrets each arranged on one compoundslide, with the tool turret which is located approximately in front ofthe main spindle, in the direction of the main spindle axis, beingprovided with the synchronous device, while the cutting-off is performedwith the second tool turret located approximately beside the mainspindle axis.

It is also advantageous for the third, rear tool carrier to be soarranged that, e.g., an inside machining tool insertable in it and thesynchronous spindle axis are so alignable with respect to one another,that they flush with one another. For then a workpiece which has justbeen cut-off can also be machined with a stationary inside machiningtool held in the rear tool carrier.

The statement above that the third tool carrier ought to be on the sideof the tool turret facing away from the main spindle does not mean thatthe third tool carrier is located opposite the main spindle workpiecechuck means with respect to the tool turret; this is firstly not thecase if the axis of rotation of the tool turret forms an angle otherthan a right-angle with the main spindle axis, and, secondly, the thirdtool carrier may also be so arranged that a workpiece held in the turretworkpiece chuck means can already be machined with it if the turret,after the cutting-off of this workpiece, was turned through an angle ofless than 180°, since it is only necessary to swivel the workpiece whichhas just been cut-off out of the area in front of the main spindleworkpiece chuck means. A construction wherein a workpiece which has justbeen cut-off is machinable by a tool held by the third tool carrierafter a rotation of the tool turret through approximately 180° is,however, preferable.

As already mentioned, in the known automatic turret lathe with asynchronous device, the turret workpiece chuck means is coupled to themain spindle mechanically, namely via a gear. In the case of anautomatic lathe according to the invention it is, however, recommendablefor the turret workpiece chuck means to have a separate drive motorwhich is electrically synchronizable with the main spindle so as toenable the machining of a workpiece with a tool of the third toolcarrier to be performed independently of the machining of the workpieceheld by the main spindle. It is particularly recommendable to have theturret workpiece chuck means driven by a direct current motor.

In a preferred embodiment of the automatic lathe according to theinvention, the second workpiece chuck means, i.e., the turret workpiecechuck means, is a pressure medium .[.acutated.]. .Iadd.actuated.Iaddend.chuck means, and a hydraulic actuation is particularlyrecommendable. In this way, the disadvantage of the known synchronousdevice is avoided, namely that while a workpiece is gripped in theturret workpiece chuck means, the latter is displaced relative to theworkpiece. Furthermore, the turret workpiece chuck means is actuatableindependently of the position of the turret slide, which is not the casewith the synchronous device of the known automatic lathes described atthe outset and is of considerable advantage in connection with theejection of a .[.machine.]. .Iadd.machined .Iaddend.workpiece.

As already mentioned, the invention is not only applicable to automaticlathes wherein the axis of rotation of the tool turret extends at rightangles to the main spindle axis since, in particular, in NC automaticlathes, the simultaneous displacement of the turret slide along bothaxes of the compound slide system creates no difficulties. If the toolturret axis of rotation is inclined at an angle α with respect to themain spindle axis, it is expedient to align the third tool carrier suchthat a machining tool insertable in it forms an angle of (180°-2α) withthe main spindle axis, to, e.g., be able to bore with a stationaryboring appliance and driven turret workpiece chuck means.

Finally, it may be recommendable to provide the third, rear tool carrierwith several tool receptors and/or with a rotatable and drivable toolreceptor so as to be able to drive an insertable tool or an insertabletool holder.

Further features, advantages and details of the invention are apparentfrom the enclosed claims and/or from the ensuing description and alsofrom the attached drawings of two particularly advantageous embodimentsof an automatic lathe according to the invention.

FIG. 1 is a schematic top view of the structural components of anautomatic NC turret lathe according to the invention which are affectedby the invention;

FIG. 2 is a front view of the structural components shown in FIG. 1,seen in the direction of the arrow A in FIG. 1; and

FIG. 3 is a presentation corresponding to FIG. 1 of a second embodimentwith a tool turret axis of rotation extending at an incline to the mainspindle axis.[...]. .Iadd.; and

FIG. 4 corresponds substantially to FIG. 2, but shows another embodimentof the invention with the stationary third tool carrier comprising atool turret. .Iaddend.

FIGS. 1 and 2 show a machine bed 10 and a headstock 12 of the automaticlathe. Mounted for rotation in the latter is a main spindle 14 whichcomprises at its front end a workpiece chuck means 16 in the form of aconventional collet chuck and which is, furthermore, provided with agear ring 18 via which and a drive pinion 20 it is driven by a firstdirect current motor M₁. The main spindle 14 takes the form of a hollowshaft, which enables a stock rod 22 to be pushed through it and theworkpiece chuck means 16. The main spindle axis was designated 24.

On the machine bed 10 there are Z guides 26 which extend parallel to themain spindle axis 24 and on which a lower slide 28 of a compound slidesystem is slidably guided. The lower slide comprises X guides 30 whichextend horizontally and vertically to the Z guides and along which anupper slide 32 of the compound slide system is slidably guidedvertically to the drawing plane. In accordance with a standard featureof automatic NC turret lathes, a separate drive, not illustrated, isprovided for the drive of the lower slide and the upper slide 28 and 32,respectively.

Mounted for rotation in the upper slide 32 in a manner not illustratedis a turret indexing shaft 36. Associated with the turret indexing shaftare drive means, also not illustrated, to enable it to be rotated in theupper slide 32. The angle of rotation position of the turret indexingshaft 36 can be monitored by a resolver or the like and set with the aidof the machine tool control. The turret indexing shaft comprises at itsfront end a tool turret 38 with a turret head 40 which, as is apparentfrom FIG. 2, comprises a twelve-cornered cross-section and, therefore,has twelve stations, so that the tool turret can be indexed onerespective station further by rotation of the turret indexing shaft 36through 30°. In one of these stations there is a synchronous device 42consisting substantially of a so-called synchronous spindle 44 mountedfor rotation in the turret body 40 and of a workpiece chuck means 46,for example, in the form of a collet chuck, carried by the synchronousspindle. At its inside end, the synchronous spindle 44 carries a pinion48 which engages with a crown wheel 50 which is a component of a driveshaft 52 mounted for rotation in the turret indexing shaft 36. The driveshaft carries at its rear end a crown gear 54 over which and a secondcrown gear 56 there extends a toothed belt 58. The crown gear 56 sits onthe shaft 60 of a second direct current motor M₂ which, like the motorM₁, is electrically connected to a control S so that, in accordance withthe invention, the main spindle 14 and the synchronous spindle 44 aresynchronously drivable.

The turret workpiece chuck means 46 is actuated by two rods 64 and 66which are articulated at an angle 70 hinged to the turret body 40 at 68,and the first of which is arranged for longitudinal displacement in thedrive shaft 52 in the form of a hollow shaft. The axis of the driveshaft 52 coincides with the indexing axis 74 of the tool turret 38. Therear end of the rod 64 carries the piston 76 of a stationary,double-acting hydraulic cylinder 78 which is connected to a hydraulicsystem 80 via two leads 82 and 84.

The hydraulic system includes a pump 86, a tank 88 and a 4-path-valve 90so that the rod 64 can be pushed forward and back in the direction ofthe turret indexing axis 74. The workpiece chuck means 46 can be closedand opened by the corresponding motions of the rod 66. Sincecorrespondingly actuated collet chucks are known, it is unnecessary toprovide a detailed description or a drawing of the workpiece chuck means46.

Finally, the automatic lathe comprises a second tool turret .[.10.]..Iadd.100 .Iaddend.with an indexing axis 102 mounted on a compound slidesystem.[., not illustrated,.]. .Iadd.(126, 128, 130, 132) .Iaddend.andarranged in the headstock 12, so that it is displaceable in a known wayin the drawing plane of FIG. 1 vertically to the main spindle axis 24and .[.vertically to the drawing plane.]. .Iadd.parallelthereto.Iaddend.. Of the tools of this second tool turret, only acutting-off tool 106 is shown in FIG. 1.

In accordance with the invention, the automatic lathe comprises inaddition to the tool turrets 38 and 100 a third, rear tool carrier 110,which may be stationarily secured to the machine bed 10 and have, forexample, three tool receptors 112 for various tools 114. In theembodiment shown in FIGS. 1 and 2, the axes of the tool receptors 112extend parallel to the main spindle axis 24 and are located on the samelevel as it, as is apparent from FIG. 2.

The automatic lathe according to the invention may be used as follows:After the front end of the stock rod 22 protruding from the main spindleworkpiece chuck means 16 has been machined by tools, not illustrated, ofthe tool turrets 38 and/or 100, the tool turret 38 is positioned bydisplacement of its compound slide system 28, 32 and by rotation aboutits indexing axis 74 so that the axis 120 of the synchronous spindle 44is flush with the main spindle axis 24, whereupon, with the workpiecechuck means 46 open, the tool turret 38 is pushed forward along the Zaxis so far in the direction towards the main spindle workpiece chuckmeans 16 that the workpiece 122 formed by the front stock rod end entersthe synchronous device 42. The synchronous spindle 44 is then drivensynchronously with the main spindle 14 with the aid of the directcurrent motor M₂ and the workpiece is gripped in the chuck means 46,whereupon it can be cut-off smoothly, i.e., without a projection, fromthe stock rod 22 with the aid of the tool 106. Subsequently, the toolturret 38 is rotated through 180°, so that after the chuck means 16opens, the stock rod 22 can immediately be pushed forward slightly so asto machine a new workpiece with tools of the tool turret 100. If thepreviously cut-off workpiece 122 is to be subjected to further machiningon the rear side, for example, provided with a bore, the tool turret 38is moved by its compound slide system up to the third tool carrier 110,as is apparent from FIGS. 1 and 2, so as to make a .[.corresonding.]..Iadd.corresponding .Iaddend.bore with the aid of one of the tools 114with the synchronous spindle 44 in driven operation. The rear side ofthe workpiece 122 may, of course, also be machined in a different way;for example, it would be possible to turn the rear end face of theworkpiece by the tool turret 38 being made to pass by a turning chiselheld by the tool carrier 110 in the direction of the X axis with thesynchronous spindle 44 in running operation.

It is, of course, also conceivable to place the tool carrier 110 on acompound slide system so that with the aid of tools of the tool turret38 both a workpiece held by the chuck means 16 and a previously cut-offworkpiece can be machined with the aid of the tools of the tool carrier110. Furthermore, the third tool carrier can take the form of anindexable tool carrier, in particular, a tool turret .Iadd.(FIG. 4)..Iaddend.If the third tool carrier rests on a compound slide system, itis adequate for the tool .[.turrent.]. .Iadd.turret .Iaddend.38 to bedisplaceable solely parallel to the main spindle axis 24.

The same reference numerals were used for the second embodiment shown inFIG. 3 as in FIGS. 1 and 2, but with the addition of a prime. Thissecond embodiment differs from the first described one only in that theturret indexing axis 74' forms with the main spindle axis 24' not aright-angle but an acute angle α; accordingly, the axis of thesynchronous spindle 44' also forms with the indexing axis 74' the sameangle α. In accordance with the invention, the third tool carrier 110'is so oriented relative to the main spindle axis 24' that the axes 112a'of its tool receptors 112' form with the main spindle axis 24' an angle(180°-2α) so that the axis of the synchronous spindle 44' after anindexing motion of the tool turret 38' through 180° can be made to beflush with the axis 112a' of one of the tool receptors.

As is apparent from a turning chisel and a boring bar in FIG. 1, thesynchronous spindle axis 120 and the tool 114 which is just beingemployed do not have to be coaxially flush with one another-this is onlythe case with a simple stationary boring appliance 114 and thesynchronous spindle 44 in driven operation. From a boring bar on, anapproximate parallelism to the synchronous spindle axis 120 issufficient, and a turning chisel may be oriented in any way with respectto this axis.

What is claimed is:
 1. An automatic turret lathe comprising a mainrotatable spindle; means for rotatably mounting said spindle forrotation about a main spindle axis; drive means associated with saidmain spindle for rotatably driving the same about said main axis; afirst workpiece chuck means associated with said main spindle androtatable therewith; a first tool carrier comprising a tool turretrotatably mounted about an indexing axis; a second workpiece chuck meansmounted on the first tool carrier turret for rotation about an auxiliaryspindle axis; a second tool carrier for machining a workpiece held bysaid first chuck means located adjacent the latter for movement relativeto a workpiece held by the first chuck means; a stationary third toolcarrier disposed on the side of said first tool carrier facing away fromsaid first chuck means; said third tool carrier carrying a plurality oftool holders; and cross slide means on which said first tool carrier isrotatably mounted for movement of said turret along axes normal andparallel to said main spindle axis so that by appropriate adjustment ofsaid slide means and appropriate indexing of said tool turret saidauxiliary spindle axis can be brought into axial alignment with saidmain spindle axis and a workpiece held by said second chuck means mayapproach each of said tool holders of the third tool carrier.
 2. Theautomatic lathe according to claim 1, in which the .Iadd.indexing.Iaddend.axis .[.of rotation.]. of the first tool carrier .Iadd.turret.Iaddend.is inclined at an angle α relative to the main spindle axis,.[.ad.]. .Iadd.and .Iaddend.a .[.machining.]. tool .Iadd.held by.Iaddend..[.mounted in.]. the .[.second.]. .Iadd.third .Iaddend.toolcarrier forms an angle of 180°-2α with the main spindle axis.
 3. Theautomatic lathe according to claims 1 or 2 in which the .[.second.]..Iadd.third .Iaddend.tool carrier has a rotatable and drivable toolholder. .Iadd.
 4. The automatic lathe according to claim 1 in which thestationary third tool carrier comprises an indexable tool turret..Iaddend. .Iadd.5. An automatic turret lathe comprising a main rotatablespindle; means for rotatably mounting said spindle for rotation about amain spindle axis; drive means associated with said main spindle forrotatably driving the same about said main axis; a first workpiece chuckmeans associated with said main spindle and rotatable therewith; a firsttool carrier comprising a tool turret rotatably mounted about anindexing axis; a second workpiece chuck means mounted on the first toolcarrier turret for rotation about an auxiliary spindle axis; a secondtool carrier for machining a workpiece held by said first chuck meanslocated adjacent the latter for movement relative to a workpiece held bythe first chuck means; a stationary third tool carrier disposed on theside of said first tool carrier facing away from said first chuck means;said third tool carrier carrying at least one tool holder; and crossslide means on which said first tool carrier is rotatably mounted formovement of said turret along axes normal and parallel to said mainspindle axis so that by appropriate adjustment of said slide means andappropriate indexing of said tool turret said auxiliary spindle axis canbe brought into axial alignment with said main spindle axis and aworkpiece held by said second chuck means may approach each tool holderof the third tool carrier. .Iaddend. .Iadd.6. The automatic latheaccording to claim 5, in which the indexing axis of the first toolcarrier turret is inclined at an angle α relative to the main spindleaxis, and a tool held by the third tool carrier forms an angle of180°-2α with the main spindle axis. .Iaddend. .Iadd.7. The automaticlathe according to claims 5 or 6 in which the third tool carrier has arotatable and drivable tool holder. .Iaddend. .Iadd.8. The automaticlathe according to claim 5 in which the stationary third tool carriercomprises an indexable tool turret. .Iaddend. .Iadd.9. The automaticlathe according to claim 5 in which said third tool carrier carries aplurality of tool holders each of which can be approached by a workpieceheld by said second chuck means by appropriate adjustment of said crossslide means and appropriate indexing of said first tool carrier turret..Iaddend. .Iadd.10. An automatic turret lathe comprising a machine bed;a main rotatable spindle; means for rotatably mounting said spindle forrotation about a main spindle axis; first drive means associated withsaid main spindle for rotatably driving the same about said main axis; afirst workpiece chuck means associated with said main spindle androtatable therewith; a first tool carrier comprising a tool turretrotatably mounted about an indexing axis; first cross slide meansmounted on said bed on a first side of said main spindle axis, said toolturret being mounted on said first cross slide means for movementthereof along axes parallel to said main spindle axis and normalthereto; a second workpiece chuck means mounted on the first toolcarrier turret for rotation about an auxiliary spindle axis; seconddrive means associated with said second chuck means for rotatablydriving the same about said auxiliary spindle axis; a second toolcarrier for machining a workpiece held by said first chuck means locatedadjacent the latter; second cross slide means mounted on said bed on asecond side of said main spindle axis, said second tool carrier beingmounted on said second cross slide means for movement thereof relativeto a workpiece held by the first chuck means along axes parallel to saidmain spindle axis and normal thereto; a stationary third tool carrierdisposed on the side of said first tool carrier facing away from saidfirst chuck means, said third tool carrier carrying at least one toolholder for holding a tool; said first tool carrier turret being mountedsuch that by appropriate first and second adjustment of said first crossslide means and appropriate first and second indexing of said first toolcarrier turret, respectively, said auxiliary spindle axis can be broughtinto axial alignment with said main spindle axis and a workpiece held bysaid second chuck means may approach said tool held by said tool holderof the third tool carrier. .Iaddend. .Iadd.11. The automatic latheaccording to claim 10, in which the indexing axis of the first toolcarrier turret is inclined at an angle α relative to the main spindleaxis, and a tool held by the third tool carrier forms an angle of180°-2α with the main spindle axis. .Iaddend. .Iadd.12. The automaticlathe according to claims 10 or 11 in which the third tool carrier has arotatable and drivable tool holder. .Iaddend. .Iadd.13. The automaticlathe according to claim 10 in which the stationary third tool carriercomprises an indexable tool turret. .Iaddend. .Iadd.14. The automaticlathe according to claim 10, in which said third tool carrier carries aplurality of tool holders each of which can be approached by a workpieceheld by said second chuck means by appropriate adjustment of said firstcross slide means and appropriate indexing of said first tool carrierturret. .Iaddend.